"Mental and emotional health can be uncomfortable topics in general, but even more so for those who are unsure how to broach the subject or are unfamiliar with the appropriate language surrounding it," the authors write. "Without proper training and guidance on how to discuss these sensitive topics, some might find it easier not to talk about them at all."

15Five also surveyed 500 managers and found that more than a quarter of the managers who received no training prior to taking on a leadership role say they never or very rarely ask about their direct reports' emotional health. This is 10 percentage points higher than managers who said they received at least some training. However, 79 percent of all of the managers surveyed say they want more managerial and leadership training.

"Genuine conversations and consistent human connection have the power to bridge gaps — whether they are educational, generational or hierarchical," the authors write. "But there's a fine line between engaging with employees regularly and micromanaging. A healthy routine of communication facilitates transparency, and garners trust and honesty from both parties. Without those two traits, conversations and one-on-ones can't include discussions about mental and emotional health, let alone job dissatisfaction and performance issues."

For employees who have at least weekly check-ins, 73 percent are extremely confident in their managers' ability as leaders; 84 percent are always honest with their manager; 56 percent think their one-on-ones are very productive and useful; 58 percent have asked for personal advice during a one-on-one; 61 percent say their managers are extremely open to suggestions; and 52 percent use their companies' employee assistance programs.

On the other hand, for employees with less than weekly check-ins, 41 percent are extremely confident in their managers' ability as leaders; 58 percent are always honest with their manager; 29 percent think their one-on-ones are very productive and useful; 29 percent have asked for personal advice during a one-on-one; 27 percent say their managers are extremely open to suggestions; and 28 percent use their companies' employee assistance programs.

Weekly one-on-one meetings between workers and their managers also benefits the entire organization, according to the survey results.

"The ROI speaks for itself: 50 percent of employees who have very productive and useful one-on-ones plan to stay at their organizations for five or more years," the authors write. "In other words, supporting the whole employee is an incredible retention tool. Not only do supported, engaged and happy employees contribute to a positive, human-centric work culture, but their support trickles down to the customer experience."

15Five recommends that employers follow a one-on-one checklist:

• Establish a regular cadence. Make sure that conversations are consistent. Try 30 minutes once a week to start.
• Encourage two-way communication. Discussions are only effective when both parties are engaged and participatory.
• Prepare an agenda use time effectively by having a concept of the conversation flow before meeting.
• Do your homework. Come with talking points, objectives and priorities gathered from the previous week.
• Begin by touching base. Get a pulse on how both of you are feeling. Building trust will encourage honesty.
• End with action items. Assemble key takeaways from the conversation as objectives for the next one-on-one.

Read more: 

• Millennials want more employer support for well-being
• Well-being important to employees, even those who lack it
• Addressing emotional wellness in the workplace